Sprinkler systems for turf irrigation are well known. Typical systems include a plurality of valves and sprinkler heads in fluid communication with a water source, and a centralized controller connected to the water valves. At appropriate times the controller opens the normally closed valves to allow water to flow from the water source to the sprinkler heads. Water then issues from the sprinkler heads in predetermined fashion.
There are many different types of sprinkler heads, including above-the-ground heads and “pop-up” heads. Pop-up sprinklers, though generally more complicated and expensive than other types of sprinklers, are thought to be superior. There are several reasons for this. For example, a pop-up sprinkler's nozzle opening is typically covered when the sprinkler is not in use and is therefore less likely to be partially or completely plugged by debris or insects. Also, when not being used, a pop-up sprinkler is entirely below the surface and out of the way.
The typical pop-up sprinkler head includes a stationary body and a “riser” which extends vertically upward, or “pops up,” when water is allowed to flow to the sprinkler. The riser is in the nature of a hollow tube which supports a nozzle at its upper end. When the normally-closed valve associated with a sprinkler opens to allow water to flow to the sprinkler, two things happen: (i) water pressure pushes against the riser to move it from its retracted to its fully extended position, and (ii) water flows axially upward through the riser, and the nozzle receives the axial flow from the riser and turns it radially to create a radial stream. A spring or other type of resilient element is interposed between the body and the riser to continuously urge the riser toward its retracted, subsurface, position, so that when water pressure is removed the riser assembly will immediately return to its retracted position.
The riser assembly of a pop-up or above-the-ground sprinkler head can remain rotationally stationary or can include a portion that rotates in continuous or oscillatory fashion to water a circular or partly circular area, respectively. More specifically, the riser of the typical rotary sprinkler includes a first portion (e.g. the riser), which does not rotate, and a second portion, (e.g. the nozzle assembly) which rotates relative to the first (non-rotating) portion.
The rotating portion of a rotary sprinkler riser typically carries a nozzle at its uppermost end. The nozzle throws at least one water stream outwardly to one side of the nozzle assembly. As the nozzle assembly rotates, the water stream travels or sweeps over the ground.
The non-rotating portion of a rotary sprinkler riser assembly typically includes a drive mechanism for rotating the nozzle. The drive mechanism generally includes a turbine and a transmission. The turbine is usually made with a series of angular vanes on a central rotating shaft that is actuated by a flow of fluid subject to pressure. The transmission consists of a reduction gear train that converts rotation of the turbine to rotation of the nozzle assembly at a speed slower than the speed of rotation of the turbine.
During use, as the initial inrush and pressurization of water enters the riser, it strikes against the vanes of the turbine causing rotation of the turbine and, in particular, the turbine shaft. Rotation of the turbine shaft, which extends into the drive housing, drives the reduction gear train that causes rotation of an output shaft located at the other end of the drive housing. Because the output shaft is attached to the nozzle assembly, the nozzle assembly is thereby rotated, but at a reduced speed that is determined by the amount of the reduction provided by the reduction gear train.
Alternatively, the drive mechanism may include a stepper motor coupled to the transmission in place of the turbine. Unlike the turbine, a stepper motor provides a constant rotational drive source which is easily electrically controlled. However, such a stepper motor is located within the sprinkler body, and typically is positioned within the water flow path in the riser. Consequently, the motor housing and the related wires protruding from the housing must be waterproofed to prevent water related motor malfunction.
Further, sprinklers (including a motorized sprinkler) typically rely on mechanical watering arc adjustments located on the sprinkler to control which areas a sprinkler head rotates through when watering. Consequently, a user must mechanically set each arc adjustment at each sprinkler location. Since an irrigation system may have many sprinklers, determining and setting individual sprinkler arcs at each sprinkler site can consume a large amount of time, especially if the irrigation system is installed over a large area such as a golf course.
Another feature of many prior art sprinklers is the use of electrically actuated pilot valves which connect inline with the irrigation water supply and a sprinkler, allowing the water flow to an individual sprinkler to be turned on or off, preferably from a distant central control system. Typically, these pilot valves are located partially or even completely outside the sprinkler body. Thus, when the pilot valve needs adjustment or replacement, a user must shut off the water supply leading to the pilot valve, dig around the sprinkler to find the pilot valve, replace the pilot valve, rebury it, then turn the water supply back on. Since the main water supply must be shut off, other sprinklers will not function during this time consuming repair and may interrupt preprogrammed watering cycles.
Although the prior art sprinklers discussed above have been known to operate with general satisfaction, there is always a need to pursue improvements. For example, prior art sprinklers do not always provide the desired accuracy in rotating the nozzle. Nor do they typically offer easy ways to maintain or repair the sprinkler. Nor do they offer the user a way to remotely control or remotely reconfigure the sprinkler. In these and other respects, therefore, the prior art sprinklers are known to have substantive limitations.
What is needed is a motorized sprinkler that senses the position of the riser nozzle, allowing the watering arc to be modified at a distant location. What is also needed is a sprinkler having a waterproof motor housing to prevent water related damage to the sprinkler motor. Further, what is needed is a sprinkler that incorporates external sprinkler components, such as a pilot valve, within the sprinkler body for easy access during repair and replacement.